Grantee Research Project Results
1997 Progress Report: Means for Producing an Entirely New Generation of Lignin-Based Plastics
EPA Grant Number: R825370C032Subproject: this is subproject number 032 , established and managed by the Center Director under grant R825370
(EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
Center: Center for Air, Climate, and Energy Solutions
Center Director: Robinson, Allen
Title: Means for Producing an Entirely New Generation of Lignin-Based Plastics
Investigators: Sarkanen, Simo
Institution: University of Minnesota
EPA Project Officer: Aja, Hayley
Project Period:
Project Period Covered by this Report: January 1, 1996 through January 1, 1997
RFA: Exploratory Environmental Research Centers (1992) RFA Text | Recipients Lists
Research Category: Center for Clean Industrial and Treatment Technologies (CenCITT) , Targeted Research
Objective:
The research project is dedicated to developing the basic technology necessary for establishing a plant where the first biodegradable plastics that are truly lignin-based can be manufactured. The industrial byproduct lignin for producing these plastics is to be isolated from kraft black liquor generated by a pulp mill in International Falls, Minnesota.Rationale: The conversion of wood chips to pulp for manufacturing paper generates huge quantities of byproduct lignins annually in the United States. The best estimates indicate that more than 26 million tons of kraft lignins are generated as byproducts of such pulping operations every year. As steps have been taken to maximize production, the recovery furnaces in an ever increasing number of mills have become overloaded; the result is that all the byproduct lignin can no longer be used in its traditional role as a fuel.
Unfortunately the necessary capital investment usually precludes construction of a new recovery furnace so that there is little prospect of rectifying the situation in the majority of recovery-loaded mills. Even though untreated black liquor cannot be discharged directly into rivers, an exacerbation of pollution originating from pulp mills is likely to occur. It is difficult to envisage a more compelling way of responding to the problem than by creating biodegradable plastics from the kraft lignin in surplus black liquor.
Intensive efforts have been under way for twenty years to incorporate surplus byproduct lignins from pulp mills into useful plastics. Until 1994 it had been thought that most polymeric materials inevitably become brittle and weak when their lignin contents exceed 25-40%. However, the first 85% industrial kraft lignin-based thermoplastics with promising tensile strengths were reported by the principal investigator in 1995 and a more detailed description of this work appeared two years later.
More recently, through CenCITT funded work, alkylated 100% kraft lignin-based plastics with comparable tensile properties have been produced in the principal investigator's research group. Thus the proposed work seeks to develop feedstocks suitable for injection-molding biodegradable plastic components that are composed entirely of simple industrial kraft lignin derivatives.
Approach:
Ultrafiltration is being employed to purify and fractionate industrial kraft lignin samples that, after simple derivatization, can be extrusion-molded into strong plastic components. The compositions of the resulting preparations are being monitored through chromatographic analysis and molecular weight determinations.
The plasticizers being sought for use with the new alkylated kraft lignin-based plastics are themselves ultimately expected to be kraft lignin-based also. It is intended that these will be made from narrow fractions of kraft lignin component derivatives carrying substituents that enhance their tendency to associate selectively with high molecular weight kraft lignin species. The development of effective kraft lignin-based plasticizers relies heavily upon testing with low molecular weight aromatic compounds possessing substitution patterns deemed likely to create this critical aspect of their function.
The final step in making these new biodegradable plastics involves spray-drying aqueous suspensions of the kraft lignin derivatives to produce powders that will be pelletized for extrusion-molding purposes.
Status:
In the quest to broaden the range of thermoplastic formulations with very high lignin contents, the feasibility of creating polymeric materials composed of 95-100% alkylated kraft lignin has been amply confirmed. From the perspective of all previous accomplishments, this is remarkable.
Kraft lignin preparations were alkylated with the corresponding dialkyl sulfates in solution at pH 11-12. Solvent-casting from DMSO of the alkylated derivatives thus produced yielded plastics containing 95-100% alkylated kraft lignin that exhibited very encouraging mechanical properties. In contrast to the previous results with 85% kraft lignin-based plastics, variations in the degree of association between the individual molecular components before derivatization seem to have no effect upon the tensile properties of the corresponding alkylated kraft lignin-based polymeric materials. This arises from the casting conditions employed, where heavy association is promoted.
It has recently been found that removal of low molecular weight kraft lignin components by ultrafiltration yields improved preparations for successful plastic formulations. This was readily evident with the ethylated higher molecular weight kraft lignin fraction obtained by ultrafiltration through a 10,000 nominal molecular weight cutoff membrane, which exhibited better plastic tensile behavior than the parent preparation.
Numerous trials have been performed in searching for signs of plastic deformation and attempting to understand the basis of plasticizing activity in alkylated kraft lignin-based plastics. Polymeric materials containing 95% (w/w) of the ethylated methylated high molecular weight kraft lignin fraction blended with appropriately substituted plasticizers have indeed exhibited plastic behavior. Under tensile stress, the materials approach a region of plastic deformation before fracture.
Since the strong non-bonded orbital interactions between the aromatic moieties of the kraft lignin components lead to brittleness in these polymeric materials, plasticizers will play a decisive role in achieving successful plastic formulations. Without explicitly disclosing information with potential proprietary value, it can be said that effective plasticizers have now been established to be compounds which preferentially interact with the kraft lignin components in such a way as to increase their chain segmental mobility. After the substituents which efficiently impart plasticizing activity have been completely or largely documented, the low molecular weight kraft lignin components themselves are destined to be derivatized accordingly into compounds that effectively fulfill this function.
Journal Articles:
No journal articles submitted with this report: View all 10 publications for this subprojectSupplemental Keywords:
RFA, Scientific Discipline, Geographic Area, Sustainable Industry/Business, Midwest, Chemical Engineering, cleaner production/pollution prevention, Sustainable Environment, Chemistry, State, Technology for Sustainable Environment, Civil/Environmental Engineering, Civil Engineering, New/Innovative technologies, Engineering, Environmental Engineering, Minnesota, biodegradable, polbiny acetate, environmentally conscious manufacturing, pulp, lignin, polymers, biodegradable materials, innovative technology, International Falls, Minnesota, plastics, innovative technologies, pollution prevention, polymer designMain Center Abstract and Reports:
R825370 Center for Air, Climate, and Energy Solutions Subprojects under this Center: (EPA does not fund or establish subprojects; EPA awards and manages the overall grant for this center).
R825370C032 Means for Producing an Entirely New Generation of Lignin-Based Plastics
R825370C042 Environmentally Conscious Design for Construction
R825370C046 Clean Process Advisory System (CPAS) Core Activities
R825370C048 Investigation of the Partial Oxidation of Methane to Methanol in a Simulated Countercurrent Moving Bed Reactor
R825370C054 Predictive Tool for Ultrafiltration Performance
R825370C055 Heuristic Reactor Design for Clean Synthesis and Processing - Separative Reactors
R825370C056 Characterization of Selective Solid Acid Catalysts Towards the Rational Design of Catalytic Reactions
R825370C057 Environmentally Conscious Manufacturing: Prediction of Processing Waste Streams for Discrete Products
R825370C064 The Physical Properties Management System (PPMS): A P2 Engineering Aid to Support Process Design and Analysis
R825370C065 Development and Testing of Pollution Prevention Design Aids for Process Analysis and Decision Making
R825370C066 Design Tools for Chemical Process Safety: Accident Probability
R825370C067 Environmentally Conscious Manufacturing: Design for Disassembly (DFD) in De-Manufacturing of Products
R825370C068 An Economic Comparison of Wet and Dry Machining
R825370C069 In-Line Copper Recovery Technology
R825370C070 Selective Catalytic Hydrogenation of Lactic Acid
R825370C071 Biosynthesis of Polyhydroxyalkanoate Polymers from Industrial Wastewater
R825370C072 Tin Zeolites for Partial Oxidation Catalysis
R825370C073 Development of a High Performance Photocatalytic Reactor System for the Production of Methanol from Methane in the Gas Phase
R825370C074 Recovery of Waste Polymer Generated by Lost Foam Technology in the Metal Casting Industry
R825370C075 Industrial Implementation of the P2 Framework
R825370C076 Establishing Automated Linkages Between Existing P2-Related Software Design Tools
R825370C077 Integrated Applications of the Clean Process Advisory System to P2-Conscious Process Analysis and Improvement
R825370C078 Development of Environmental Indices for Green Chemical Production and Use
The perspectives, information and conclusions conveyed in research project abstracts, progress reports, final reports, journal abstracts and journal publications convey the viewpoints of the principal investigator and may not represent the views and policies of ORD and EPA. Conclusions drawn by the principal investigators have not been reviewed by the Agency.
Project Research Results
Main Center: R825370
155 publications for this center
36 journal articles for this center